Since powder made of iron-based metallic glass has an excellent magnetic property when it is molded by compacting powders, it is expected to be widely used for magnetic materials to be used to manufacture electronic components, such as inductors and choking coils.
Some kinds of amorphous iron-based metallic glass have been discovered in the past. Since the conventional iron-based metallic glass was manufactured by adding many rare elements (rare metals), such as Ga, Pd, and Zr, to obtain a stable amorphous structure, the cost to manufacture it was high. Further, it was manufactured in a non-oxidizing atmosphere under a great degree of supercooling, to obtain a stable amorphous structure. Though the iron-based metallic glass that is manufactured in this way has a good magnetic property, in practice it has not been used due to its cost.
The degree of supercooling is defined by ΔTx, which is calculated by this equation:ΔTx=Tx−Tg, where Tx: the recrystallization temperature, and
Tg: the glass-transition temperature.
To solve these problems, iron-based metallic glass that consists of elements that are comparatively cheap, and that can be manufactured in the atmosphere, was proposed in Japanese Patent Laid-open Publication No. 2002-080949. However, the proposed iron-based metallic glass contains, in addition to Fe, large amount of Co, Ni, and Mo as essential elements. These elements are more expensive than Fe. Thus its cost would increase.
Japanese Patent Laid-open Publication No. 2005-290468 proposes iron-based metallic glass that contains no expensive rare metal, is based on iron, which is a cheap element, and has an amorphous structure that is easily obtained in the atmosphere. The proposed iron-based metallic glass should be preferably used for electronic materials, since it has a good magnetic property. However, components of technically advanced electronic devices, such as a magnetic core for a mobile terminal, have recently been required to have a higher corrosion-resistance.
The objects of the present invention are to solve the problems and to provide powder made of the iron-based metallic glass that has an improved magnetic property, an improved insulating property, and an improved corrosion-resistance, based on the powder that is made of the iron-based metallic glass in Japanese Patent Laid-open Publication No. 2005-290468.